Why is this battery covered in stickers?
More straight answer 
Because Apple would confiscate Apple logo repair parts outside Apple Authorised distribution in the name of copyright infringement .
Why?
Because Apple wants to monopolise their hardware department as they have done successfully their software department
Why?
Because Apple can do what they want, the Best Business Practice (^_^)/
iPhone — Environment — Apple
No repair, sell refurbish at inflated price? No more independent repairers are able to point out the iPhone 6/7 Design Flaw : Flexion based damage.
Consequence ?
The consumers are so scared to use non- authorised repairers (including restart volunteers) and parts through this business practices with heavy FUD marketing.
Please don’t play brand sectarian war please. Don’t belong to Team Apple, Google etc, you just simply failed to see the bigger picture. We have already seen this business practice.
I bought a “genuine” Toshiba Laptop note battery from China last year, the brand name on the battery was hidden as Janet found. I have confirmed that this was genuine with a battery check utility, as the 18650 Lithium Batteries were made by LG.
Toshiba was so innovative that they have blocked to supply user manuals in the name of copyright protection long time ago? (I posted Google mailing list before ) Apple just pushes this idea further.
https://ifixit.org/blog/3743/operation-fix-toshiba-help-us-write-repair-manuals/
Happy repairing ! (is under atack…)